Gas turbines are commonly used as a power source to drive electrical generating equipment (such as in an electrical power station) or for propulsion (e.g., for aircraft, marine vessels, or military equipment such as tanks). A combustion type gas turbine has a gas path, which typically includes, in a serial-flow relationship, an air intake (or inlet), a compressor, a combustor, a turbine, and a gas outlet (or exhaust nozzle). A controller governs the operation of the turbine. The controller includes a processor for generating control signals in response to a plurality of turbine operating conditions. Control of the power generated by the gas turbine is typically exercised through control of fuel flow and airflow into the combustor.
Modern gas turbine engines employ a gas-fired (“lean”) premixed combustion system, known as a Dry Low Emissions (DLE) combustion system. DLE combustion systems are designed to reduce the emissions of nitrous-oxides (NOx), carbon monoxide (CO), unburned hydrocarbons (UHC), particulates, and other pollutants to levels well below those achievable with older combustion systems. DLE combustion systems employ combustors having a dual or triple dome design, with staging of fuel flow and air flow to achieve lean-premixed operation from light-off to full power. This technology permits the operator to run with reduced emissions of pollutants over a wide load setting, in addition to meeting all other design requirements including high combustion efficiency and low levels of combustion dynamics.
Combustor mapping is the process of measuring operational boundaries for an individual gas turbine engine and translating this data into control schedules for use by the controller of that engine. This process is required for each engine because engine-to-engine (or, more correctly, system-to-system) variability on maximum/minimum operational boundaries and ring flame temperature control may be greater than the allowable operating window. Each engine is required to be mapped during site commissioning to measure and compensate for this variability. Due to the drift or shift of the boundaries with time or due to significant maintenance (replacement of a combustor for example), additional mapping and subsequent control system adjustments are sometimes required during the life of the engine.
Combustor mapping is a manual, iterative process requiring the accurate observation of multiple engine parameters and the manual collection of the observed parameters. These observations must be made for many burner mode and bleed setting combinations. As a result, combustor mapping is tedious, and time consuming, with the potential of human error. In addition, special classroom and hands-on training are required to become qualified to properly map a particular engine. This training increases the money and time cost of the combustor mapping process.